health_get_lifetime_stats

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description fully carries the burden. It discloses that results are cache-bounded, includes a coverage block with specific fields, and explicitly states absence of tracker split and active score. This goes well beyond a generic read, providing actionable caveats.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is succinct and front-loaded with the main purpose. It uses three short paragraphs/sentences, each adding distinct value: purpose, breakdown of records, and important caveats. No filler or redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given there is an output schema, the description doesn't need to detail return values, but it still explains the coverage block and its importance. It covers what the tool does, its limitations, and how to interpret results—sufficient for a no-param read operation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters, so the description naturally adds no parameter syntax. Per the baseline for 0-param tools, a score of 4 is appropriate—there is nothing to compensate for.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb-resource statement: 'Get all-time activity totals and personal best records.' It clearly defines scope (totals for steps, floors, distance, calories) and distinguishes from siblings like health_get_activity by noting exclusions (no tracker-versus-total split, no active score).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It provides clear context on data freshness ('bounded by what has been synced') and instructs to read the coverage block before quoting totals as all-time. It does not explicitly name alternative tools for missing features, but it does state what this tool does not provide, which guides selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.